Many medicament delivery devices are developed for self-administration, i.e. the user performs the delivery. This requires a delivery device which is as safe and easy to handle as possible.
In order to meet the requirements, the risk of human errors must be minimized, the number of actions needed to be performed in order to receive a dose need to be reduced and the device must be intuitive and ergonomic to use.
In order to minimize the risk of human errors, it is desirable to have the device as pre-assembled as possible.
One solution for keeping the device as pre-assembled as possible is to deliver the medicament injection device with a delivery member such as a needle, a nozzle or the like, pre-attached. This solution often causes the rear end of the delivery member to protrude into the interior of the container, which could be a drawback if the medicament reacts with the material of the delivery member when exposed for a period of time. In that respect it would be desirable to have the rear part of the delivery member outside the container until the delivery is to be performed.
WO 2009/150078 A1 discloses an injection device wherein the cartridge is penetrated by the needle upon intention of using the device. The needle is coaxially held by a hub such that the needle is extended both in a proximal and in a distal direction from the hub. The hub is axially movable in relation to and interactively connected to a retainer member. A cap is interactively connected to the retainer member and has protrusions interactively connected with grooves on the outer periphery of the hub, such that when the cap is manually operated, it causes the hub to move in a distal direction such that the distal end of the needle penetrates the container.
To minimize the number of actions needed in order to perform the injection, some devices only need to be pressed against the injection area, without the need of injecting by pressing a button or the like, which causes the needle to penetrate the injection area and the device perform the injection. Thereby, the delivery procedure is reduced by at least one step.
One such device is disclosed in patent document EP 1349590 B describing an injector having a number of features that facilitate the handling of the injector. The penetration and injection is performed manually by simply pressing the proximal end of a needle shield against the delivery area, causing the shield to move in a distal direction, enabling the needle to penetrate the injection area and thereafter initiate the injection process. When the injection is performed the injector is withdrawn whereby a needle shield extracts around the needle in a locked way.
Another aspect of injectors is the human aspect of handling the injection device regarding how it is held during operation. A general aim is to have the patient holding the injector in an ergonomic way that permits penetration and injection in different locations on the body, such as around the waist and also on the backside of the waist and/or in the buttocks of the patient. The patient does not see the injector at those locations and need to be able to hold the injector without having to change grip. By removing the action of pushing a button or the like, the patient is free to hold the device as he desires and feels comfortable.
However, a drawback with needle shield activated devices such as the device in EP 1349590 is the need to use syringes, since the activated shield covers the delivery member and hinders the insertion of delivery members. The need of syringes is a drawback since syringes are more expensive and more difficult to handle than cartridges.